recently ,i am working on the atomization of liquid . with fluent 6.1 ,I also selected a single point injection in a axisymmetrical case, steady calculation, under spray model ,choose the droplet breakup and collision. The problem is that the the mass flow rate in the monitor for convergency check is always equal to zero!

monitor set as follow: Solve- Monitors -Volume. (a)Increase the number of monitors to 1. (b) Turn on Plot and Print and click Define.... (c) Under Field Variable, select Discrete Phase Model... and DPM Mass Source. (d) Under Cell Zones, select fluid i am very confused about it ,waiting for your answers 3X!!!